3) (30 points) You have the following rates of return for a risky portfolio for several recent years. Assume that the stock pays S1 dividend at year end. Year #shares bought or sold 2004 2005 2006 Beginning of year price $50 $55 $51 $54 100 bought 50 bought 75 sold 75 sold 2007 a. What is the arithmetic average return over the entire time period? b. What is the geometric average return for the period